Cooled seal cartridge

ABSTRACT

A cooled seal cartridge assembly applicable to a pump as a unit and containing a stub shaft, a double mechanical seal and a heat exchanger through which cooling fluid is circulated by an axial flow impeller which carries the rotatable carbon rings of the mechanical seals, and a fan circulates air over the heat exchanger.

D United States Patent 1 1 1111 3,884,482 Ball et al. May 20, 1975 [54]COOLED SEAL CARTRIDGE 3,600,101 8/1971 (S)glesby 6 1972 [75] Invemors:Rowlmd Long Beach; 3322358 371973 27796 Winfred J. Wiese, Whittier, bothof Calif. OTHER PUBLICATIONS [73] Assigneec Borg wamer (:orporafion,chicagc Drawing lF6235, Seal and Bearing Assembly, by Ball,

1" November 1968.

[22] Filed: Mar. 8, 1973 Primary Examiner-Samuel B. Rothberg 21 App| 337 Attorney, Agent, or Firm-John 0. Evans, Jr.

[52] US. Cl. 277/17; 277/22; 277/41 [57] ABSTRACT 51 1m. (:1 F16j 15/40A Cooled Seal camldge assembly applicable to a P [58] Field of Search277/3, 16,22, 17 as U and containing a Stub shaft. 8 double chamcal sealand a heat exchanger through which [56] References Cited cooling fluidis circulated by an axial flow impeller UNITED STATES PATENTS whichcarries the rotatable carbon rings of the me- 2 494 887 H1950 L h 277/22chanical seals, and a fan circulates air over the heat en art 3,459,4308/1969 Ball 1 277/3 exchanger 3,489,419 1/1970 Stratienko 277/22 X 13Claims, 2 Drawing Figures 1 A 22 U 2/ I2 2? 5a 52 E 4r /9 Z Z7 45 Z? 4/49 7 /4Z 40 fig 5a 9,? 44

,2 1 52 344 a? l 94 a 5 25 l 35 3e 5e 8/ 75 79 i Q I PATEN-TED HAY20|9753. 884, 482

SHEET 2 BF 2 COOLED SEAL CARTRIDGE BACKGROUND OF THE INVENTION Theprovision of a mechanical seal assembly for preventing leakage along arotary shaft extending into or through a housing, such as a pumphousing, has involved the utilization of double and tandem seals, eachincluding a pair of complemental relatively rotatable seal ringsrespectively carried by the housing and the shaft through suitablemounting means. Where high temperature fluids are encountered, the sealassembly, and more particularly the seal rings may be cooled by acoolant fluid circulated through the seal chamber and through asurrounding heat exchanger. To assist in cooling, the heat exchanger maybe exposed externally of the housing or may be subjected to air flowinduced by a fan rotatable with the shaft.

However, such assemblies are, in general composed of sub-assemblies andcomponents which require substantial work to assemble and disassemblethe seal and cooling components, notwithstanding the existence ofcertain cartridges or seal assemblies which are susceptible ofpreliminary assembly and subsequent installation in the seal chamber ofthe housing as a unit.

SUMMARY OF THE INVENTION The present invention involves and has as anobject the provision of an improved cartridge or mechanical sealassembly which can be more readily and easily installed on a pump shaft,without entailing complex and time consuming disassembly and assemblyprocedures.

The cartridge of the invention is adapted to be completely assembledoutside of a pump or other device having a rotary shaft, and installedas a unit containing a stub shaft connectable to the rotary shaft, apair of mechanical seal sub-assemblies each including a pair ofrelatively rotatable seal rings, one of the rings of each pair beingrotatable with the stub shaft and the other ring being non-rotatablyconnected to a housing which defines the seal chamber and through whichthe cooling fluid is circulated by an axial flow impeller rotatable withthe stub shaft and driving the respective rotatable seal rings, wherebyfluid friction and heat are minimized, and the housing has removablydisposed thereon a heat exchanger jacket, which is separatelyreplaceable without disassembly of the cartridge from the pump shaft. Afan for forcing cooling air over the heat exchanger jacket and a fanshroud are adapted to be installed on the stub shaft and the jacket. Themechanical sealing structure includes sub-assemblies of a seal ring andpre'loading springs that are initially held in condition for assembly inthe seal housing by novel retainer means.

The cartridge seal of the invention is well suited to installation inthe usual intermediate support or housing between a pump case and pumpdrive motor through an access opening or window, without requiringdisassembly of the motor assembly from the pump assembly. Theintermediate housing is adapted to support a reservoir for the coolingfluid, the reservoir having conduits adapted to be easily connected toand disconnected from the seal cartridge housing during assembly anddisassembly of the cartridge unit between and from between the motorshaft and rotary shaft to be sealed.

The present invention possesses many other advantages, and has otherpurposes which may be made more clearly apparent from a consideration offorms in which it may be embodied. These forms are shown in the drawingsaccompanying and forming part of the present specification. They willnow be described in detail, for the purpose of illustrating the generalprinciples of the invention; but it is to be understood that suchdetailed descriptions are not to be taken in a limiting sense, since thescope of the invention is best defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view partly inlongitudinal section and partly in elevation, illustrating a cooledmechanical seal cartridge installed between a pump shaft and a motorshaft; and

FIG. 2 is a longitudinal section through the cartridge assembly, on anenlarged scale, showing its mounting on the pump case, with the stubshaft shown partially in elevation and partially in broken section.

DESCRIPTION OF THE PREFERRED EMBODIMENT As seen in the drawings,referring first to FIG. 1, the seal cartridge S is interposed between amotor housing M and a pump housing P in an elongated intermediatehousing 10 or other structure located between the motor housing M andthe pump housing P which connects the housings M and P together inspaced relation. In the illustrated structure, the motor housing M hasan end flange 11 providing an opening 12 through which an end 13 of amotor shaft projects. The intermediate housing or support 10 comprises acylindrical or other tubular body suitably welded at 14 in the opening12 to the plate 11 and having at its other end a flange 15 adapted to beconnected by fasteners 16 to an end plate 17 of the pump assembly P. Atone side, the intermediate housing or support 10 is open, as by theprovision of a window 18 which provides access to the seal cartridgeassembly S and to connector means 19 by which the motor shaft 13 isadapted to drive the rotary pump shaft 20.

This connector means 19 comprises a connector sleeve 21 keyed by a key22 on the motor shaft 13 and having an internal shoulder 23 for limitingdownward movement of the sleeve 21 on the shaft 13, but the sleeve 21being free for axial upward movement on the shaft 13. On the sleeve 21is a connector flange 24 connectable by fasteners 25 to a coupling 26which is in turn connected by fasteners 27 to an upper flange 28 formedon or made a part of a stub shaft 29 which forms part of the sealcartridge S and which extends into a socket 30 in the upper end of thepump shaft 20, wherein the stub shaft 29 is connected to the pump shaftfor rotation as a unit by an axially extended key 31 engaging in akeyway 31a on the stub shaft 29. The stub shaft 29 has a bolt 32extending axially therethrough and threaded with the pump shaft 20 toreleasably hold the stub shaft and the pump shaft against axialseparation, as will be later described.

The seal cartridge S comprises a cylindrical body 33, adapted to containthe mechanical seal means hereinafter to be described, and about. whichis disposed a tubular jacket 34 defining with the body 33 a helical flowpassage 34a for cooling fluid which is circulated through the sealassembly, as will also be later described. To assist in cooling thejacket 34 it is provided with radiating ribs 35 and longitudinallyextended grooves 36 through which air is forced by a fan 37. This fan 37has blades 38 carried by a support ring 39 which rests on a radiallyoutwardly projecting flange 40 on the stub shaft flange 28, the ringbeing keyed to the flange 28, as at 41, for rotation therewith and beingretained in place upon connection of the coupling sleeve 26 to the stubshaft flange 28 by the fasteners 27. A shroud 42 is provided about thefan 37 by a longitudinally split body 43 having a lower, inwardlyprojecting shoulder 44 adapted to engage in an external groove 45 in theribs 35 of the jacket 34 when the split shroud is disposed about thejacket and removably secured in place by radially outwardly projectingflanges 45 and fasteners 46 which provide a clamping means. At its upperend the shroud may be provided with a suitable screen 47.

Cooling fluid is adapted to be supplied to the seal body 33 from areservoir 48 suitably made a part of or connected to the intermediatemember 10, or otherwise conveniently located. Conduits 49 and 50 leadbetween the reservoir and suitable fittings, such as the fitting 51 onthe seal body 33 and connectors 52 at the reservoir. The reservoir maybe appropriately provided with suitable fill and bleed fittings 53 and54, and a drain fitting 55, as well as with a pressurizing fitting orvalve 56, whereby the cooling fluid may be pressurized as desired,depending upon the conditions under which the mechanical sealing meansare to be operated.

Ordinarily, the pressure of the cooling fluid would be set at a valuesomewhat in excess of the pressure of the fluid in the pump case P, sothat any leakage through the seal assembly S results in cooling fluidpassing along the stub shaft 29, rather than in the loss of fluid fromthe pump case.

By way of example, the seal assembly is shown as applied to a pumpassembly of the type which may pump high temperature liquidfbut whereina blanket of gas may be provided between the pump liquid and the sealassembly S. In this illustrative structure, which generally correspondsto that shown in US. Pat. No. 3,630,529, granted Dec. 28, 1971, a vaportrap designated by the general reference numeral 60 is interposedbetween the shaft and a head plate 61 of the pump case P for the purposeof substantially preventing the escape of vapor along the shaft 20 andacross the head. The vapor trap has a stationary member 62 carried bythe head 61 and a rotary member 63 carried by the shaft 20.

The rotary member 63 has a cylindrical portion 64 fitted to the shaftsection 20b. The rotary member 63 is locked to the shaft section by ascrew 65. A cylindrical section 66 of the rotary member 63 carriesaxially spaced, outwardly projecting, downwardly sloping baffles in theform of fins 67, sloped downwardly at an angle at approximately 30fromthe horizontal. The rotary member 63 has a cap portion 68 with 21depending skirt 69. The cap overlies the stationary member 62 and isspaced slightly therefrom so that it may rotate freely withoutinterference. An O-ring 70 seals the rotary member to the shaft section20.

The stationary member 62 of the trap is welded to the pump head 61 at 71and has a plurality of inwardly projecting baffle members 72 positionedopposite to the spaces between the fins 67 on the rotary member. Theinner diameters of the baffle members 72 are slightly greater than theouter diameters of the fins 67 of the rotary member; this enables therotary member'to be inserted into and removed from the stationarymember.

Above the trap 60 is a domed member 74 which is connected at its outerperipheral flange 75, by fasteners 76, to the head plate 61, a suitablering seal 77 being interposed between the flange and the plate. At thetop of the domed member 74 is a tubular member 78 which is disposedabout the stub shaft 29 in circumferentially spaced relation to anothertubular member 79 which, as will later be described, forms part of theseal assembly S. A third tubular member 80 projects upwardly from thedomed member 74 in outwardly, radially spaced relation to the tubularmember 78 and forms withthe latter an annular well 81 into which thelower end of the tubular member 79 extends. The height of the outermosttubular body 80 is less than the height of the innermost tubular body78, whereby cooling fluid which leaks through the seal assembly willpredominantly flow over the outermost tubular body 80 and thence to alow groove 82 in the plate 61 from which the cooling fluid may beperiodically drained through a drain passage 83 normally closed by asuitable valve 84.

Above the upper pump plate 61 the intermediate support structure 10 hasa horizontal member 85, shown as a plate, provided with a centralopening in which the seal assembly S is mounted by bolts 86. This sealassembly S is shown in detail in FIG. 2.

The body 33 of the seal assembly S is of cylindrical form and has anupper end flange and a lower end flange 91, respectively secured to theends of the body 33 by fasteners 92 and 93. A ring seal 94 is disposedbetween the top plate 90 and the upper end of the body 33, and a ringseal 95 is disposed between the lower end of the body 33 and the flange91.

The top flange 90 has an inner, cylindrical sleeve section 97, in whichis disposed non-rotatable sealing ring means 98, including a ring 99having a radial seal face 100, the ring 99 being sealed on the sleevesection 97 by the usual packing ring 101 which is expanded by anexpander and drive ring 102. The expander and drive ring 102 is suitablykeyed to the seal ring 99, as by coengageable lugs at 103, and the ring102 is also suitably keyed, as by lugs and ribs at 104, to a retainerring 105, which is in turn secured by fasteners 106 to the top flange90. A number of coiled compression springs 102a are disposed between thetop flange 90 and the expander and drive ring 102 and normally bias thenonrotatable sealing ring 99 axially away from the end flange 90.

In order to enable the sealing ring means 98 to be initially installedas a sub-assembly on the end flange 90, before the latter is secured tothe body 33, the retainer ring has a radially inturned flange 105aconstituting an abutment engageable by an outstanding abutment 99a onthe seal ring 99, whereby expansion of the springs 102a is limited andthe seal ring 99 is retained on the skirt section 97 of the end flange90.

The lower end flange 91 corresponds to the upper flange 90 and has askirt 197 on which non-rotatable sealing ring means 198 are disposed,including the seal ring 199 with a radial seal face 200, the packing201, the expander and drive ring 202 which is keyed to the seal ring 199and to a retainer 205 which is secured to the flange 91 by fasteners 206and initially holds the compression springs 202a and seal ring 199. Thislower non-rotatable sealing means will, accordingly, be understood toprovide a sub-assembly with the lower flange 91 in the same manner asdescribed above with respect to the upper non-rotatable sealing ringmeans 98, without need for further detailed description.

Between the opposed radial seal faces 100 and 200 of the non-rotatablesealing ring means 98 and 198 are rotatable sealing ring means 110,providing a radial seal face 111 opposed to the radial seal face 100 ofthe seal ring 99 and a radial seal face 112, opposed to the radial sealface 200 of the seal ring 199. These seal faces 111 and 112 are formedon rotatable seal rings, such as carbon rings, 113 and 114,respectively, carried in bores 115 and 116 in a common carrier ring 117which is keyed at 118 to the shaft 29 and held against a radial shoulder119 by a threaded collar 120 engaged with companion threads 121 on areduced stub shaft section 122. Static ring seals 122a are disposedbetween the seal rings 113 and 114 and the carrier 117 in the bores 115and 116 to prevent fluid from passing around the seal rings 113 and 114.

In the illustrative embodiment the collar 120 is locked in place by aset screw 123 which engages in a groove 124 in the stub shaft 29. Inaddition, the tubular member 79 previously described is formed as a partof the collar 120 for simplicity of construction.

As will now be apparent, the housing or body 33 and its end flanges 90and 91 cooperate with the stub shaft 29 to form a chamber for themechanical sealing ring means comprising the opposed non-rotatablesealing ring means 99 and 199 and the intermediate rotatable sealingring means 110. In addition the mechanical sealing ring means definewith the housing 33 a cooling fluid chamber 125 which is incommunication at its opposite ends, via ports 125a and 125b, withannular spaces 126 and 127 which in turn communicate with the helicalflow passage 34a within the heat exchanger sleeve 34. Cooling fluid issupplied to the chamber 125 from the reservoir, as previously describedvia the conduits 49 and 50, the latter communicating with the annularspace 127 and the former communicating with the chamber 125 via porting125C in the end flange 90.

In the present embodiment, cooling fluid is circulated through thecooling fluid chamber 125, as shown by the arrows in FIG. 2, by an axialflow impeller 128 formed as part of the rotatable ring carrier 117 whichhas an outer peripheral helical ridge 129 to induce flow. Since therotatable sealing ring means 110 is a simple structure and therelatively complex structures of the sealing ring means 98 and 198remain non-rotatable, the heat of fluid friction is minimized.

The cooling jacket 34 is applicable to and removable from the body 33 inan endwise manner. To enable this, the body has a cylindrical outer wall130 over which the jacket 34 fits, and a lock ring 131 engaged beneaththe top flange 90 retains the jacket 34 in place. Seal rings 132 and 133are disposed between the body 33 and cylindrical inner walls at the topand bottom of the jacket 34. If desired, the jacket and body may bepinned, as at 134 to prevent the jacket from rotating on the body.

In the assembly of the seal assembly S, the upper flange 90, with thenon-rotatable sealing ring means 98 retained thereon by the retainer105, is placed endwise over the lower end of the stub shaft 29, and,then, the rotatable sealing ring means 110 is applied to the shaft andsecured in place by the collar 120. Thereafter, the body 33, with orwithout the cooling jacket is assembled endwise, over the lower end ofthe stub shaft 29 and the sealing ring means 98 and 110, and fastened tothe top flange 91). The lower end flange 91, with the non-rotatablesealing ring means 198 retained thereon, as above described, is thenapplied over the lower end of the shaft 29 and connected to the body 33.If the jacket 34 was not previously applied to the body 33, this is thendone to complete the cartridge assembly as seen in FIG. 2, which canthen be assembled with the pump shaft 20 and the support structure 10 bythe through bolts 32 and 86.

This assembly of the seal cartridge S with the pump shaft can beaccomplished through the side opening 18 in the intermediate supportstructure 10, in the absence of the coupling sleeve 26. The fan 37 andthe shroud 42 can then be applied. Thereafter thecoupling 19 can becompleted to interconnect the motor shaft 13 with the stub of the sealcartridge.

A reverse dis-assembly procedure is also possible, and therefore, thepresent invention provides for rapid installation, service, replacementor repair of the seal assembly S.

We claim:

1. A sea] assembly applicable to a rotary shaft to prevent fluid leakagebetween said rotary shaft and a case comprising: a housing having meansfor mounting the housing on said case, a stub shaft rotatable in saidhousing and having means connectable to said rotary shaft, said housingincluding means defining a seal chamber between said housing and saidstub shaft, mechanical said means in said chamber for preventing fluidleakage between said stub shaft and said housing, said mechanical sealmeans forming with said housing a cooling fluid chamber, said housinghaving an inlet for said cooling fluid chamber and an outlet for saidcooling fluid chamber, a cooling jacket disposed about said housing andhaving means providing a flow path therein for cooling fluid flow, meansconnecting one end of said flow path to said inlet and means connectingthe other end of said flow path to said outlet, whereby cooling fluidmay flow from said outlet through said flow path, through said inlet,and through said cooling fluid chamber from said inlet to said outlet,and cooling fluid impelling means rotatable with said stub shaft forcausing cooling fluid flow through said cooling fluid chamber from saidinlet to said outlet, wherein said housing has a cylindrical outersurface, said cooling jacket being in the form of a sleeve applicableendwise to said housing, said housing and said sleeve having meansforming end seals therebetween, and one of said housing and said coolingjacket having groove means in its surface between said end seals andconfronted by the other of said cooling jacket and said sleeve, saidgroove means providing said flow path for cooling fluid flow.

2. A sea] assembly as defined in claim 1, including air fan meanscarried by said stulb shaft for forcing air over said cooling jacket.

3. A seal assembly as defined in claim 1, including air fan meanscarried by said stulb shaft for forcing air over said cooling jacket,and shroud means for said fan carried by said jacket.

4. A seal assembly as defined in claim 1, including air fan meansremovably carried by said stub shaft, and shroud means for said fanremovably carried by said cooling jacket.

5. A seal assembly as defined in claim 1, wherein said means connectableto said rotary shaft comprises a bolt extending through said stub shaftand key means on said stub shaft.

6. A seal assembly as defined in claim 1, including means releasablyretaining said jacket on said housing.

7. A seal assembly as defined in claim 1, including means defining anexternal cooling fluid reservoir and means for connecting said reservoirto said flow path for cooling fluid flow.

8. A seal assembly as defined in'claim 1, said means defining a sealchamber comprising end flanges removably secured on said housing, andsaid means for mounting said housing on said case including fastenermeans removably connecting said housing to said case, whereby saidhousing, said end flanges and said jacket are removable from said caseas a unit.

9. A seal assembly as defined in claim 8, said means defining a sealchamber comprising end flanges removably secured on said housing, andsaid means for mounting said housing on said case including fastenermeans removably connecting said housing to said case, said mechanicalseal means comprising non-rotatable and axially shiftable seal ringcarried by said end flanges, and each of said seal rings having aradially extended face, and a pair of rotatable seal rings carried bysaid cooling fluid impelling means and each having a radial face opposedby the radial face of the respective non-rotatable seal rings.

10. A seal assembly as defined in claim 9, including compression springmeans interposed between said end plates and said non-rotatable sealrings and expansible to bias the latter towards said rotatable sealring, and retainer means carried by said end plates, said nonrotatableseal rings and said retainer means having abutment means for limitingexpansion of said spring means during assembly.

11. A seal assembly as defined in claim 8, said mechanical seal meanscomprising non-rotatable and axially shiftable seal rings carried bysaid end flanges, each of said seal rings having a radially extendedface, and rotatable seal ring means carried by said stub shaft forrotation therewith and having radial faces opposed by the radial facesof the respective non-rotatable seal rings.

12. A mechanical seal cartridge comprising: a rotatable stub shaft, ahollow housing disposed about said stub shaft, end flanges disposedabout said stub shaft, means releasably connecting said end flanges tosaid housing, each of said end flanges carrying nonrotatable sealingring means including an axially shift able seal ring having a radialseal face, the radial seal face of the respective seal rings beingdisposed in opposing axially spaced relation, rotatable sealing ringmeans carried by said stub shaft for rotation therewith and providingoppositely facing radial seal faces for engagement by said radial sealfaces of the respective axially shiftable seal rings, and spring meansinterposed between said end flanges and said axially shiftable sealrings for biasing the latter towards said rotatable sealing ring meansto effect said engagement of said radial seal faces, and including acooling jacket disposed about said housing and having means defining acooling fluid flow path therein, said housing having a pair of axiallyspaced ports leading between said cooling fluid flow path and theinterior of said housing, said cooling fluid flow path, said pair ofspaced ports, and said interior of said housing defining a fluid flowcircuit wherein fluid may flow from said interior of said housing,through one of said pair of ports, through said cooling fluid flow path,through the other of said pair of ports, and back into said interior ofsaid housing, and said rotatable sealing ring means including coolingfluid impelling means.

13. A mechanical seal cartridge comprising: a rotatable stub shaft, ahollow housing disposed about said stub shaft, end flanges disposedabout said stub shaft, means releasably connecting said end flanges tosaid housing, each of said end flanges carrying non rotatable sealingring means including an axially shiftable seal ring having a radial sealface, the radial seal face of the respective seal rings being disposedin opposing axially spaced relation, rotatable sealing ring meanscarried by said stub shaft for rotation therewith and providingoppositely facing radial seal faces for engagement by said radial sealfaces of the respective axially shiftable seal rings, and spring meansinterposed between said end flanges and said axially shiftable sealrings for biasing the latter towards said rotatable sealing rings meansto effect said engagement of said radial seal faces, a cooling jacketdisposed about said housing and having means defining a cooling fluidflow path therein, said housing having a pair of axially spaced portsleading between said cooling fluid flow path and the interior of saidhousing, said cooling fluid flow path, said pair of spaced ports, andsaid interior of said housing defining a fluid flow circuit whereinfluid may flow from said interior of said housing, through one of saidpair of ports, through said cooling fluid flow path, through the otherof said pair of ports, and back into said interior of said housing, andsaid rotatable sealing ring means including cooling fluid impellingmeans, said rotatable sealing ring means comprising a carrier ringmounted on said stub shaft, said carrier ring having oppositely openingaxial bores, seal rings in said bores having said radial seal facesthereon, and static sealing means between said seal rings in said boresand said carrier ring.

1. A seal assembly applicable to a rotary shaft to prevent fluid leakagebetween said rotary shaft and a case comprising: a housing having meansfor mounting the housing on said case, a stub shaft rotatable in saidhousing and having means connectable to said rotary shaft, said housingincluding means defining a seal chamber between said housing and saidstub shaft, mechanical said means in said chamber for preventing fluidleakage between said stub shaft and said housing, said mechanical sealmeans forming with said housing a cooling fluid chamber, said housinghaving an inlet for said cooling fluid chamber and an outlet for saidcooling fluid chamber, a cooling jacket disposed about said housing andhaving means providing a flOw path therein for cooling fluid flow, meansconnecting one end of said flow path to said inlet and means connectingthe other end of said flow path to said outlet, whereby cooling fluidmay flow from said outlet through said flow path, through said inlet,and through said cooling fluid chamber from said inlet to said outlet,and cooling fluid impelling means rotatable with said stub shaft forcausing cooling fluid flow through said cooling fluid chamber from saidinlet to said outlet, wherein said housing has a cylindrical outersurface, said cooling jacket being in the form of a sleeve applicableendwise to said housing, said housing and said sleeve having meansforming end seals therebetween, and one of said housing and said coolingjacket having groove means in its surface between said end seals andconfronted by the other of said cooling jacket and said sleeve, saidgroove means providing said flow path for cooling fluid flow.
 2. A sealassembly as defined in claim 1, including air fan means carried by saidstub shaft for forcing air over said cooling jacket.
 3. A seal assemblyas defined in claim 1, including air fan means carried by said stubshaft for forcing air over said cooling jacket, and shroud means forsaid fan carried by said jacket.
 4. A seal assembly as defined in claim1, including air fan means removably carried by said stub shaft, andshroud means for said fan removably carried by said cooling jacket.
 5. Aseal assembly as defined in claim 1, wherein said means connectable tosaid rotary shaft comprises a bolt extending through said stub shaft andkey means on said stub shaft.
 6. A seal assembly as defined in claim 1,including means releasably retaining said jacket on said housing.
 7. Aseal assembly as defined in claim 1, including means defining anexternal cooling fluid reservoir and means for connecting said reservoirto said flow path for cooling fluid flow.
 8. A seal assembly as definedin claim 1, said means defining a seal chamber comprising end flangesremovably secured on said housing, and said means for mounting saidhousing on said case including fastener means removably connecting saidhousing to said case, whereby said housing, said end flanges and saidjacket are removable from said case as a unit.
 9. A seal assembly asdefined in claim 8, said means defining a seal chamber comprising endflanges removably secured on said housing, and said means for mountingsaid housing on said case including fastener means removably connectingsaid housing to said case, said mechanical seal means comprisingnon-rotatable and axially shiftable seal ring carried by said endflanges, and each of said seal rings having a radially extended face,and a pair of rotatable seal rings carried by said cooling fluidimpelling means and each having a radial face opposed by the radial faceof the respective non-rotatable seal rings.
 10. A seal assembly asdefined in claim 9, including compression spring means interposedbetween said end plates and said non-rotatable seal rings and expansibleto bias the latter towards said rotatable seal ring, and retainer meanscarried by said end plates, said non-rotatable seal rings and saidretainer means having abutment means for limiting expansion of saidspring means during assembly.
 11. A seal assembly as defined in claim 8,said mechanical seal means comprising non-rotatable and axiallyshiftable seal rings carried by said end flanges, each of said sealrings having a radially extended face, and rotatable seal ring meanscarried by said stub shaft for rotation therewith and having radialfaces opposed by the radial faces of the respective non-rotatable sealrings.
 12. A mechanical seal cartridge comprising: a rotatable stubshaft, a hollow housing disposed about said stub shaft, end flangesdisposed about said stub shaft, means releasably connecting said endflanges to said housing, each of said end flanges carrying non-rotatablesealing ring means including an axially sHiftable seal ring having aradial seal face, the radial seal face of the respective seal ringsbeing disposed in opposing axially spaced relation, rotatable sealingring means carried by said stub shaft for rotation therewith andproviding oppositely facing radial seal faces for engagement by saidradial seal faces of the respective axially shiftable seal rings, andspring means interposed between said end flanges and said axiallyshiftable seal rings for biasing the latter towards said rotatablesealing ring means to effect said engagement of said radial seal faces,and including a cooling jacket disposed about said housing and havingmeans defining a cooling fluid flow path therein, said housing having apair of axially spaced ports leading between said cooling fluid flowpath and the interior of said housing, said cooling fluid flow path,said pair of spaced ports, and said interior of said housing defining afluid flow circuit wherein fluid may flow from said interior of saidhousing, through one of said pair of ports, through said cooling fluidflow path, through the other of said pair of ports, and back into saidinterior of said housing, and said rotatable sealing ring meansincluding cooling fluid impelling means.
 13. A mechanical seal cartridgecomprising: a rotatable stub shaft, a hollow housing disposed about saidstub shaft, end flanges disposed about said stub shaft, means releasablyconnecting said end flanges to said housing, each of said end flangescarrying non-rotatable sealing ring means including an axially shiftableseal ring having a radial seal face, the radial seal face of therespective seal rings being disposed in opposing axially spacedrelation, rotatable sealing ring means carried by said stub shaft forrotation therewith and providing oppositely facing radial seal faces forengagement by said radial seal faces of the respective axially shiftableseal rings, and spring means interposed between said end flanges andsaid axially shiftable seal rings for biasing the latter towards saidrotatable sealing rings means to effect said engagement of said radialseal faces, a cooling jacket disposed about said housing and havingmeans defining a cooling fluid flow path therein, said housing having apair of axially spaced ports leading between said cooling fluid flowpath and the interior of said housing, said cooling fluid flow path,said pair of spaced ports, and said interior of said housing defining afluid flow circuit wherein fluid may flow from said interior of saidhousing, through one of said pair of ports, through said cooling fluidflow path, through the other of said pair of ports, and back into saidinterior of said housing, and said rotatable sealing ring meansincluding cooling fluid impelling means, said rotatable sealing ringmeans comprising a carrier ring mounted on said stub shaft, said carrierring having oppositely opening axial bores, seal rings in said boreshaving said radial seal faces thereon, and static sealing means betweensaid seal rings in said bores and said carrier ring.